Cave's climate clues show ancient empires declined during dry spell

(PhysOrg.com) -- The decline of the Roman and Byzantine empires in the Eastern Mediterranean more than 1,400 years ago may have been driven by unfavorable climate changes.

Based on chemical signatures in a piece of calcite from a cave near Jerusalem, a team of American and Israeli geologists pieced together a detailed record of the area's climate from roughly 200 B.C. to 1100 A.D. Their analysis, to be reported in an upcoming issue of the journal Quaternary Research, reveals increasingly dry weather from 100 A.D. to 700 A.D. that coincided with the fall of both Roman and Byzantine rule in the region.

The researchers, led by University of Wisconsin-Madison geology graduate student Ian Orland and professor John Valley, reconstructed the high-resolution climate record based on geochemical analysis of a stalagmite from Soreq Cave, located in the Stalactite Cave Nature Reserve near Jerusalem.

"It looks sort of like tree rings in cross-section. You have many concentric rings and you can analyze across these rings, but instead of looking at the ring widths, we're looking at the geochemical composition of each ring," says Orland.

Using oxygen isotope signatures and impurities — such as organic matter flushed into the cave by surface rain — trapped in the layered mineral deposits, Orland determined annual rainfall levels for the years the stalagmite was growing, from approximately 200 B.C. to 1100 A.D.

While cave formations have previously been used as climate indicators, past analyses have relied on relatively crude sampling tools, typically small dental drills, which required averaging across 10 or even 100 years at a time. The current analysis used an advanced ion microprobe in the Wisconsin Secondary-Ion Mass-Spectrometer (Wisc-SIMS) laboratory to sample spots just one-hundredth of a millimeter across. That represents about 100 times sharper detail than previous methods. With such fine resolution, the scientists were able to discriminate weather patterns from individual years and seasons.

Their detailed climate record shows that the Eastern Mediterranean became drier between 100 A.D. and 700 A.D., a time when Roman and Byzantine power in the region waned, including steep drops in precipitation around 100 A.D. and 400 A.D. "Whether this is what weakened the Byzantines or not isn't known, but it is an interesting correlation," Valley says. "These things were certainly going on at the time that those historic changes occurred."

The team is now applying the same techniques to older samples from the same cave. "One period of interest is the last glacial termination, around 19,000 years ago — the most recent period in Earth's history when the whole globe experienced a warming of 4 to 5 degrees Celsius," Orland says.

Formations from this period of rapid change may help them better understand how weather patterns respond to quickly warming temperatures.

Soreq Cave — at least 185,000 years old and still active — also offers the hope of creating a high-resolution long-term climate change record to parallel those generated from Greenland and Antarctic ice cores.

"No one knows what happened on the continents... At the poles, the climate might have been quite different," says Valley. "This is a record of what was going on in a very different part of the world."

In addition to Valley and Orland, the paper was authored by Miryam Bar-Matthews and Avner Ayalon from the Geological Survey of Israel, Alan Matthews of the Hebrew University in Jerusalem and Noriko Kita of UW-Madison.

Provided by University of Wisconsin-Madison


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Deciphering clues to prehistoric climate changes locked in cave deposits

Citation: Cave's climate clues show ancient empires declined during dry spell (2008, December 4) retrieved 19 August 2019 from https://phys.org/news/2008-12-cave-climate-clues-ancient-empires.html
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Dec 04, 2008
Does anyone else think that outside invasion and too much lead in the water had more to do with the fall of Rome?

Dec 04, 2008
I absolutley agree with the lead theory.

Dec 04, 2008
It also explains modern Italy.

Dec 05, 2008
the dailly instalment news proganda about the
global warming
its just pyshi warfare on the minds of people

chek it out
http://www.youtub...PV01uyRs

Dec 05, 2008
Now, now come on. It is very possible that the drought lead to a decline in crop harvest and and that coupled with the slightly drier foutains....screw it. I'm going with the raging hordes of barbarians from all sides. Pretty sure the advanced irigation and aquaduct systems would have helped fight any adverse affects of drought.

Dec 05, 2008
Does anyone else think that outside invasion and too much lead in the water had more to do with the fall of Rome?


The author did not make that
conclusion! You think he did , but
not true: he merely stated a
*CORRELATION* ! and its undeiable.

At the same time, less water means
its more precious, therefore
a possible reason for using pipes!

Droughts do tend to 'unsettle
people' and might contribute to
vulnerabilities during invasions.

Note that I am not drawing any
conclusion, either!

Dec 05, 2008
Yeah, it was dry weather, had absolutely nothing to do with the secession of 1/2 the active Roman legions, the decline in trade due to invasion, lead poisoning, and general insanity of their somewhat inbred upper class. Oh, and just ignore those barbarians at the gate, they're just here for a drink since it's so dry and all.


One of the many factors in the fall of the Roman empire was the increasing need for imported staples from the client lands to feed the Roman bellies. As the empire got bigger, large shipments of grain had to come from farther afield (bad pun intended). It became a tradition (not in a good way) for Roman crowds to gather at the docks waiting for the first grain ships from Egypt. Any delay in shipments could literally cause starvation in Rome. Under these circumstance, with the system stretched to its limit, any change in climate that resulted in even a small percentage drop in production would result in chaos. "Bread and Circuses" doesn't work well without the "bread" part.


Dec 05, 2008
Lead in the water? Perhaps some contribution.

Insanity of the upper classes? Possibly a contributer, though quite commonly new emperors were nominated by the military from among their generals (Ceasar etc.) who often weren't upper class.


Lead causes many things to happen...
From the US Department of Labor:
"The health effects of lead exposure include, but are not limited to: problems with the liver; kidneys; blood-forming system; muscles and joints; and the central and peripheral nervous systems. Lead exposure is also linked to reproductive system disorders and sterility and/or impotence in males. Lead exposure may also result in irritability, fatigue, weight loss, high blood pressure, constipation, and insomnia."

Dec 06, 2008
I don't have the citation but I've read that the invasions from the North were precipitated by the beginnings of the Dark Ages Cold Period, which brought the end of the Roman Warm Period. Apparently food crops don't do well with shorter summers. I believe that the colder climate was the proximate cause of Rome's fall.

Dec 06, 2008
I know from previous articles that cave formations can be used as proxies for temperatures also, however it seems that this study avoids all mention of any temperatures. I find this odd since the Roman Optimum and the Dark Ages, are known to represent a warm period and a cold period.

Perhaps "Dry Period" is the new UN approved way to say "Ice Age".

Also:
Cold Weather=Bad Weather
Cold=Crisp
Very Cold=Quite Crisp
Snow=Bad Precipitation
Arctic Ocean=Open Water
Antarctic=Watch out for falling ice shelves
Polar Bears=Cuddly Animals in desperate danger

Modern Warm Period=Oh No, It's .7C hotter in the last 100 years!!!

Dec 06, 2008
It's interesting that the period when the climate was dry, and may have caused the collapse of different civilisations, corresponds to the dark ages cool period. Thereby confirming what Lomberg and others have been arguing that, on balance, warmth is good for civilisation.

Dec 06, 2008
This article has the word "climate" in it, and therefore it poses a challenge to my deep religious faith in global warming denialism. To prevent my faith from eroding, I seek validation from other denialists by sharing scripture from my favorite global warming denialist blog:

P1: The climate changed in the past.
C1: Therefore, humans have no effect on the environment.

http://img.photob...thod.jpg


Dec 08, 2008

I counter your poor joke with one of my own.


OK, that's it. I'm pulling the plug.

Hitler.

This thread is now officially dead.

Dec 10, 2008
This article has the word "climate" in it, and therefore it poses a challenge to my deep religious faith in global warming denialism. To prevent my faith from eroding, I seek validation from other denialists by sharing scripture from my favorite global warming denialist blog:

P1: The climate changed in the past.
C1: Therefore, humans have no effect on the environment.

http://img.photob...thod.jpg



I counter your poor joke with one of my own.

Global Warming Facts:

Humans are evil
Humans create CO2
Therefore CO2 is evil.

Sorry, mate, but that won't cut it.

Noein presented a non sequitur that frequently IS employed by those who are dismissive of AGW.

You, on the other hand, presented one that is NOT employed by those accepting of AGW.

The former is true to its intent; the latter, not so.

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